Ephedrine and its metabolites are naturally occurring alkaloids which can be derived from evergreens worldwide and have been used as medicinals for hundreds of years. Because they have pharmacological alpha and beta catecholamine effects and are natural products, the alternative medicine industry has popularized them for multiple uses including asthma, weight loss, energy and sexual enhancement, and euphoria. Several recent reviews have documented the dangerous nature of using these compounds unsupervised, including multiple deaths, and the FDA is currently reviewing ephedrine's use in the alternative medicine industry. We report a new toxicity, ephedrine nephrolithiasis, in a patient using an energy supplement, Ma-Huang extract, which contains ephedrine. Although previously not reported, the Louis C. Herring and Company kidney stone data base demonstrates that there is an endemic complication of ephedrine with hundreds of previous episodes. Using GC Mass Spectr ometry we were able to positively identify the chemical structure of our patients stone, as well as other similar stones from Louis Herring, as containing ephedrine, norephedrine, and pseudoephedrine.